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Comment by bobbles | Hacker News Reader

It seems crazy that the way to test emissions was the test what the car computer said... and not what actually came out of the car

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The "emissions cheat" in question altered the output of the car when it was being tested. So, they were testing the emissions that came out of the car.

"EPA regulators said that Volkswagen adopted a 'sophisticated' algorithm that turned on vehicles' full emissions controls when it detected they were being tested for emissions performance." - http://www.usatoday.com/story/money/cars/2015/09/18/epa-accu...

Learning from the video card industry, I see.

I remember that a couple of years back some company got into PR trouble for doing that with a fridge.

And keep in mind that VW is simply the only company who got caught. I find it hard to believe they were the first one or the only ones doing this.

There were 2 VWs and 1 BMW X5 in test and the BMW came OK.

have you ever got software certified for the government or military? It's daunting at first, you know there are problems. As the process goes along though, it's just a financial process. You pay a government contractor to write some documentation and it's the documentation that is "tested". It just takes time and it's not cheap, it has little to do with security.

The epa tests are for beaurocrats, now maybe the world is changing but I suspect that if you could simply plug a usb stick in to your car and get better mileage and more power, at the cost of some nitrogen, a ton of people would do it, maybe most would. If it was really important, they'd require the cars to have real time sensors as standard equipment and put some of the responsibility on the driver too. VAG just played along and made the game more efficient. Not that I agree with it, it sucks, but the system was built to be gamed, it's broken

Especially since, as far as I'm aware, when my car gets smogged they measure the pipe itself.

Was isn't this already in place (at least in CA)?

The testing was in place, but the software was designed to detect the testing process. A simple hack would be something like: (Hood open)or(doors open)+(Throttle>0)=I'm being tested. That would be enough to hide from standard testing procedures.

Systems designed to defeat specific test are nothing new. The biggest example I can think of are the Buell (Harley) bikes that use an exhaust bypass designed to keep the bike quite at RPMs used during the CA test.

The emissions test takes place on a dynamometer, which would result in a large number of weird things the car could test for.

Such as open doors/hood while the wheels are spinning, no acceleration or a stationary GPS signal.

The fact that cars have GPSs, make it next to impossible to design tests that can't be cheated, you would need a testing rig that could be mounted on a moving car, that didn't cause an increase of pressure on the exhaust system (cars could detect that) And then you would need to do testing on public roads, so the car didn't switch to a different mode when it's GPS showed it was on a known test track.

Volkswagen used a ECM that sensed if the vehicle was being tested based on various inputs including the position of the steering wheel, vehicle speed, the duration of the engine's operation, and barometric pressure. (source EPA.gov)

> you would need a testing rig that could be mounted on a moving car

That's how this was discovered.

In my state, PA, they use an inductive pickup on the spark plug wire for cylinder #1 to determine the RPMs and a probe that's inserted into the tailpipe. The probe is a small diameter (0.5" or less) tube and it shouldn't raise the back pressure by any appreciable amount.

Maybe an EE could tell us if it's possible for the ECM to detect the presence of the inductive pickup.

EE here. Technically it's possible to detect an inductive pickup. But they are pretty subtle. You would probably need a very specially designed coilpack.

Or, you could look at the code running in the car, which is what the EFF proposes.

You can't generally rely on GPS signal being available.

You can't, but that doesn't really affect the cheat. I mean you could do: if gps not available default to clean mode. That would benefit you during testing or when you're in an underground garage or tunnel (Places where you would like to have as clean exhaust as possible anyway).

There is talk of emissions controls being linked to GPS location so that each country/state/city might enforce different emissions rules. Some high-end Japanese machines already use GPS to determine whether or not they are on a racetrack, opening up performance and speeds normally locked away while on public roads.

I'm not sure how practical would that be: you have to conform the tightest standard out there anyway (and garages are mostly indoor venues).

It is very practical - the whole Volkswagen scandal is caused by the fact that the compromise of low emissions vs better performance and mileage can be dynamically changed by software, and that a car that can conform to the tightest standard still would prefer use a mode with higher emissions whenever and wherever allowed.

It would enable your car to suddenly perform better as soon as you enter a state with less strict emission requirements, or vice-versa, your usually high emission car would be legal to operate when visiting stricter places because it can switch to a limited more when needed.

Sounds like the ideal situation for everyone.

Are there accelerometers in cars these days? That would be another obvious test.

yes, afaik modern ABS uses accelerometers to detect if the car is skidding

No. ABS detects wheel rotation. Traction and stability control use accelerometers.

interesting! I have no Idea about cars. How do they tell the difference between going fast and slipping then?

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